A variety of methods are known for detecting behavior-based associations (associations based on user behaviors) between items stored or represented in a database. For example, the purchase histories or item viewing histories of users can be analyzed to detect behavior-based associations between particular items represented in an electronic catalog (e.g., items A and B are related because a relatively large number of those who purchased A also purchased B). As another example, the web browsing histories of users can be analyzed to identify behavior-based associations between particular web sites and/or web pages.
The detected behavior-based associations are typically used to assist users in locating items of interest. For example, in the context of an electronic catalog, when a user accesses a network resource, such as a web page, that is associated with an item, the resource may be supplemented with a list of related items. The detected associations may also be used to generate personalized recommendations that are based on the target user's purchase history, item viewing history, and/or other item selections.